????構造DataFrame

from pandas import Series,DataFrameimport numpy as npframe=DataFrame(np.arange(9).reshape((3,3)),index=['a','c','d'],columns=['ohio','texas','california'])frame Out[73]: ohio texas california a 0 1 2 c 3 4 5 d 6 7 8

????按照索引提取

frame2=frame.reindex(['a','b','c','d'])frame2 Out[75]: ohio texas california a 0.0 1.0 2.0 b NaN NaN NaN c 3.0 4.0 5.0 d 6.0 7.0 8.0

????按照columns 提取

states=['texas','utah','california'] frame.reindex(columns=states)Out[76]: texas utah california a 1 NaN 2 c 4 NaN 5 d 7 NaN 8

????按照索引和columns提取

states=['texas','utah','california'] frame.reindex(index=['a','b','c','d'],method='ffill',columns=states)Out[77]: texas utah california a 1 NaN 2 b 1 NaN 2 c 4 NaN 5 d 7 NaN 8

????簡便方法

frame.ix[['a','b','c','d'],states] Out[79]: texas utah california a 1.0 NaN 2.0 b NaN NaN NaN c 4.0 NaN 5.0 d 7.0 NaN 8.0

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